Over the past week, NuSTAR observed WISSH-49, an extremely luminous quasar from the era of cosmic noon (z = 2–4). This is as part of the WISSHFUL Large Program, a 750 ks Cycle-10 NuSTAR program coordinated with a multi-year XMM-Newton Heritage Program to observe this sample of extremely bright accreting black holes. The primary goal of the NuSTAR program is to search for Ultra-Fast Outflows (UFOs) in these targets, which requires high signal-to-noise ratio broadband X-ray data. Leveraging the unprecedented XMM-Newton time allocation, which is sensitive to redshifted iron absorption, NuSTAR enables accurate determination of the continuum, which is essential for robust UFO detections. UFOs provide one of the key diagnostics of feedback from active galactic nuclei, which is believed to play a key role in the evolution of massive galaxies.

The results from the peer review of proposals submitted for observations in cycle-3 of NASA’s Imaging X-ray Polarimetry Explorer (IXPE) was released this week and include eight proposals selected to perform coordinated observations with NuSTAR. NuSTAR performs many observations simultaneous with IXPE and provides up to 500 ksec of observing time each year to the IXPE General Observer program. There is a high demand for these observations—proposals each year request more than five times the available NuSTAR observing time, including a large proportion of proposals for coordinated Target of Opportunity observations of transient events. Due to this high demand, the NuSTAR team has agreed to accept more than 650 ksec of observations for this cycle and, although the official start of IXPE cycle-3 is not until February 2026, the first coordinated observations have already been scheduled for this month.

Authors: Daniel Stern (NuSTAR Deputy PI, JPL), Karl Forster (NuSTAR Operations Lead, Caltech)